Die for making metal foil lids



Sept. 8, 1964 Filed July 11, 1960 W. S. HOLMES DIE FOR MAKING METAL.FOIL LIDS 4 Sheets-Sheet l FIG. 2

INVENTOR/ 'WALTELS. HOLMES Arromfv s Sept. 8, 1964 Filed July 11, 1960w. s. HOLMES DIE FOR MAKING METAL FOIL 1.10s

4 Sheets-Sheet 2 INVENTOR, WALTEK'S. HOLME 5 &

ATTOIQlEYS Sept. 8, 1964 w. s. HOLMES 3,147,721

DIE FOR MAKING METAL FOIL LIDS Filed July 11, 1960 4 Sheets-Sheet 3INVENTOIL WALTEPQ. HOLMES mowers P 8, 1964 v w. s. HOLMES 3,147,721

DIE FOR MAKING METAL FOIL LIDS Filed July 11, 1960 4 Sheets-Sheet 4 FIG.7

79* I l44 7 5-}; 1' [44b g; 44o. o /44c 33 3o ATTORNEYS United StatesPatent "ice 3,147,721 DIE FOR MAKING METAL FOR LIDS Walter S. Holmes,Toronto, Ontario, Canada, assiguor, by

mesne assignments, to Reynolds Metals Company, Richmond, Va., acorporation of Delaware Filed July 11, 1960, Ser. No. 42,142 14 Claims.(Cl. 113-42) This invention relates to a die for making lids of metalfoil.

A disposable receptacle, having at its open end a peripheral outwardlyextending lip, can be provided with a tightly fitting metal foil lid bymaking the lid with a dished central portion that fits snugly into theopen end of the receptacle, and with an outer wall having an outwardlycurled bead fitting under the lip. The formation of the lid can beperformed in a sequence of operations, namely, dishing the centralportion, then bending the peripheral portion inwardly to form the outerwall, and then forming the bead.

The object of this invention is to provide a die for performing thesesequential operations.

A preferred embodiment of the invention will be described with referenceto the accompanying drawings in which like reference numerals designatelike parts and in which:

FIG. 1 is a perspective view of a plastic cup and a metal foil lidtherefor, the lid being the product of the die illustrated in FIGS. 3 to7 inclusive;

FIG. 2 is an enlarged longtiudinal sectional view through the cup andlid of FIG. 1, the bottom of the cup being broken away;

FIG. 2a is a further enlarged fragmentary sectional view of theassembled cup and lid;

FIG. 3 is a partly sectional, somewhat diagrammatic side view of a dieconstructed in accordance with the present invention for forming themetal foil lid of FIGS. 1 and 2, the upper assembly of the die being inits uppermost position;

FIG. 4 is a view similar to FIG. 3 but showing the upper die assemblymoving downwardly;

FIG. 5 is a view similar to FIGS. 3 and 4 but showing the upper dieassembly in its bottom position;

FIG. 6 is a view similar to FIGS. 3, 4 and 5 but showing the upper dieassembly moving upwardly; and

FIG. 7 is an enlarged fragmentary sectional view of the bead curlingportion of the die when in the position of FIG. 6.

FIGS. 1, 2 and 2a illustrate a cup 10 and a lid 20 for the cup. Neitherthe cup nor the lid forms part of the present invention. However anunderstanding of a suitable configuration of the lid will facilitate thedescription of the die for making it. The lid will be described withreference to a cup on which it fits.

The cup 10 has a side wall 11 that flares outwardly from the bottom ofthe cup to the open end or mouth 12 of the cup. At the mouth the wall 11has a smooth inner annular wall surface 13, and the wall curves upwardlyand outwardly to an upper circular edge 14 concentric with the surface13, and then curves downwardly and outwardly to a peripheral outwardlyextending lip 15 also concentric with the surface 13 and edge 14. Thelip 15 is preferably stiff, so that it does not easily bend inwardly.While a great variety of materials may be used for the cup 10, the cupmay for example be made of thin impact extruded plastic, such a cupbeing competitive in cost of manufacture with a cardboard cup.

The lid consists of metal foil and has a generally horizontal circularbottom 21 provided with a raised ornamental pattern 22. At the center ofthe lid is an opening 23 to permit egress and inflow of air from and tothe 3,147,721 Patented Sept. 8, 1964 cup 10 when the lid is put on andremoved. However as shown in FIG. 2 the metal 23a displaced in formingthe opening 23 extends downwardly around the opening. Around the bottom21 the lid has an inner upwardly extending wall 24. The inner wall 24flares outwardly slightly and has an outer annular surface 25 whichconforms as closely as possible to the inner annular wall surface 13 ofthe cup. From the upper edge of the wall 24 a rim 26 extends outwardlyso as to engage the upper edge 14 of the cup. Extending downwardly fromthe rim 26 is a peripheral outer wall 27 which terminates in astifiening bead 28. The head 28 curls outwardly from a circle 29 at theinner surface of the outer wall 27, the circle 29 when the lid is inplace on the cup being concentric with the lip 15 of the cup but alittle below the lip. The circle 29 is coplanar with and concentric withthe center line of the head. In the manufacture of the lid the diameterof the circle 29 is made slightly less than the diameter of the lip 15so that the inner circumference of the wall 27 at this circle isnormally slightly smaller than the circumference of the lip 15. When thelid is pressed onto the cup, the wall 27 and head 28 must expand to passover the lip, but being of metal, and thus resilient, they pull inwardlyagain when they have passed over the lip, and thus the bead engagesunder the lip and pulls the lid down onto the cup, holding the outerannular surface 25 of the lids inner wall 24 in intimate contact withthe inner annular wall surface 13 of the cup and holding the rim 26 ofthe lid in intimate contact with the upper edge of the cup. The rimlimits the downward movement of the lid on the cup and thus ensures thatthe head is properly positioned relatively to the lip 15, i.e., with thecircle 29 slightly lower than the lip. The stiffening bead 28, pullinginwardly below the lip 15, prevents accidental upward movement of thelid from the position of FIG. 2a. Thus, with the head 28 forced over thelip 15, the cup is clasped between the bead 28 and the rim 26. Theinward pull of the bead also provides a transverse clamping actionbetween the lid wall 27 outside the cup and the lid wall 24 inside thecup. Thus it is desirable for the inner wall 24 to extend downwardlyfrom the rim 26 at least as far as the plane of the circle 29, and inthe lid illustrated the wall 24 is deeper than the outer wall 27 so asto obtain a large contact area between the outer surface 25 and the cupsurface 13. Such a deep inner wall 24 helps to prevent sloshing ofliquid out of the cup even if the lid is not pulled tightly down againstthe upper edge 14 of the cup.

An important advantage of having the bottom 21 and wall 24 of the lidnested snugly in the mouth of the cup is that they reinforce andstrengthen the cup against transverse pressure that may be applied bysomeone gripping the cup or by accidental forces to which the cup may besubjected. Not only does the reinforcing action help to preventaccidental breakage of the cup before the lid is removed, but it helpsto prevent accidental dislodgment of the lid, particularly with flexiblewalled cups. A flexible walled cup under transverse pressure tends tochange from a circular to an oval shape, and a circular lid that gripsthe cup around merely the outer periphery of the cup, rather thanextending down into the cup as do the wall 24 and bottom 21, may pop offthe cup rather than prevent the deformation of the cup to oval shape.

As will be explained, the lid 20 is formed from a flat circular blank ofmetal foil. In forming the inner wall 24, rim 26 and outer wall 27 it isnecessary to dispose of excess foil. This might be done by formingregular radial pleats in the foil, but in order to obtain good contactbetween the surfaces of the lid and cup it is desirable to have the lidwalls as smooth as possible, without radial passageways between the lidand cup through which the contents of the cup may leak. Accordingly, inthe manufacture of the lid such gathering of the foil as cannot beavoided is allowed to take place in an irregular man ner (i.e. withoutdeliberate pleating) but the gatherings are scattered as uniformly aspossible over the lid portions 24, 26, 27 so that very small wrinkles 30are formed, the wrinkles being generally radial but none thelessirregular. Thus, with the bead holding the lid down on the cup, there issubstantially a seal around the mouth of the cup, and if the cup isinverted there is no loss of its contents.

Since the outer wall 27 and bead 28 are resiliently expansiblecircumferentially, the lid can be removed from the cup by an upward pullon the bead. If the bead were not provided, there would be insufficientfriction between the surfaces of the cup and lid to prevent accidentaldisplacement of the lid from the cup. The fact that the bead curlsoutwardly from the wall 27 ensures that as the lid is placed on andremoved from the cup there is no tendency for the bead to be caught andtorn open by the lip 15.

Whereas with paper cups and lids a paper taste is sometimes imparted tothe contents of the cups, particularly if the contents are hot, the foillid 20 does not affect the flavour of the contents, and the lid 20 canbe used on a cup of plastic which also does not affect the flavour. Thefoil lid 20 has low heat emissivity and high heat reflectivity, and canbe used on a cup of foamed plastic having excellent heat insulativeproperties so that the cup and lid are far superior to conventionalpaper cups and lids in holding their contents at a constant temperature.The foil has the further advantage of being hydrophobic; it does notabsorb and retain the liquid in the cup, nor become soggy, and itconsequently provides a useful dish into which the cup may be set toprevent any liquid that runs down the cup from wetting a surface onwhich the lid is placed.

The metal 23a extending downwardly around the opening 23 forms afrustro-conical baffle which helps to prevent liquid within the cup fromsloshing out through the opening. The effective area of the openingthrough the lid to allow passage of air should be equivalent to acircular hole of a diameter not less than approximately 0.03 inch; toosmall an opening through the lid appears, particularly with smoothsurfaced cups, to promote leakage around the edge of the cup. To preventloss of liquid from the cup the equivalent hole diameter should notexceed approximately 0.07 inch.

Metal up to about 0.006 inch in thickness is ordinarily considered to befoil, and while thick foil can be used to make the lid 20 it ispreferred to use as thin a gauge of foil as possible in order to keepthe cost of the lid to a minimum. Aluminum foil half hard in temper, orharder, is preferred. Such aluminum foil down to about 0.001 inchthickness has sufficient strength, and it is preferred not to exceed0.0025 inch in thickness. Thin foil has the advantage that it can easilybe marked. For example, the lid of a cup of coffee can be indented, bymeans of a pencil or similar instrument, with the letters C, S or B todesignate a cup containing, respectively, coffee with cream, coffe withsugar, or black coffee, or the lid may be made with such lettersembossed or indented therein so that the user can encircle the letter orletters appropriate to identify the contents of the cup. Anotheradvantage of thin foil is that it can be substantially consumed ordestroyed in an incinerator, whereas heavier metal creates a disposalproblem.

In a specific example, for a cup having a wall thickness of 0.017 inchand a lip of 2 /8 inch diameter, an aluminum foil lid of 0.0018 inchthickness was used, having a head 28 curled on a inch outside diameter,and having for the circle 29 in undeformed diameter 0.004 inch less thanthe diameter of the lip 15.. This difference in diameters can vary fromabout 0.001 inch to about 0.008 inch for a cup lip having approximatelythe 4 diameter mentioned. Buckling of the bottom 21 and wall 24 of thelid, as the bead passes over the lip 15, is prevented by the flexibilityof: the rim 26 and by the fact that the outer surface 25 of the wall 24conforms in diameter to the inner surface 13 of the cup.

The die of FIGS. 3 to 7, and the operation of the die, will be describedin detail below, but the formation of the lid 20 in the die can be seenfrom a brief inspection of FIGS. 3 to 7. The sequence of operations ofthe die is from the fully open position of FIG. 3 through the partlyclosed position of FIG. 4 to the fully closed position of FIG. 5 andthen back through the partly closed position of FIG. 6 to the fully openposition of FIG. 3. As the die closes from the fully open position ofFIG. 3, a flat circular blank is severed from a sheet 32 of metal foil,and the central portion of the blank is dished to the shape shown inFIG. 4 to form the inner lid wall 24- and bottom 21. During the dishingoperation the peripheral portion 33 of the blank is pulled inwardlyaround the central portion 34. As the peripheral portion is pulledinwardly, it is smoothly and uniformly gripped between the plane endsurfaces of gripping rings 60 and of FIGS. 3 and 4, the pressure exertedon the gripped peripheral portion being sufliciently light that theperipheral portion can slip inwardly without tearing as the blank isdished. Inward slipping of the peripheral portion is essential duringthe dishing of the central portion since foil cannot stretch or drawappreciably without tearing. The uniform pressure around the peripheralportion ensures that the wrinkling of the foil caused by the dishing ofthe central portion is irregular but generally radial and scattered allaround the inner wall 24 and peripheral portion 33, as alreadydescribed.

During the movement of the die from the position of FIG. 4 to that ofFIG. 5 the peripheral portion 33 is bent inwardly, as shown in FIG. 5,to form the outer wall 27 of the lid, the rim 26, and the annualr recess35 between the dished central portion 34 and the peripheral portion 33.During the return movement of the die from the position of FIG. 5 tothat of FIG. 6, the stiffening head 28 is formed by curling the edge ofthe peripheral portion outwardly and then inwardly through approximately360 degrees, as shown in FIGS. 6 and 7. The completed lid 20 can then beremoved as the die returns to the fully open position of FIG. 3.

Now considering the die construction in detail, an upper die assembly 36is, as shown in FIG. 3, normally spaced from a lower die assembly 37,being reciprocable downwardly (the forward movement) and upwardly (thereturn movement) by any conventional means, for example by a flywheeland crankshaft (not shown). The components of the upper die assembly aremounted on an upper die block 38, and include a downwardly facing femalepunch 40. The main body 41 of the female punch 40 is fixed totheunderside of the die block 38 by studs 42, but the punch also includes aknockout 43 which can be depressed downwardly with respect to the punchbody 41. The knockout has a head 44 the lower surface 45 of which formspart of the fact of the punch. A plunger 46 fast with the head 44extends slidably upwardly through aligned passages 47 in the body 41 anddie block 38, and the plunger protrudes from the top of the die blockwhere the a collar 48 is fastened to it. A spring 49 in compressionbetween the collar and the die block normally prevents the knockout frommoving downwardly relatively to the die block 38 and punch body 41.

The female punch 40 has a peripheral end wall 50 defining a recess 51 inthe face of the punch. The bottom surface 45, 52 of the recesscorresponds in shape to the outer surface of the bottom 21 of the lid tobe formed, ridges 53 being provided on the knockout corresponding to thepattern 22 on the bottom of the lid. A central cylindrical opening 54 isprovided for formation of the opening 23 and metal baffle 23a of thelid, as will be.

5, described. The inner surface 55 of the end wall 50 corresponds inshape to the outer surface 25 of the inner wall 24 of the lid, that isto say, it corresponds in shape to the cups inner annular wall surface13 again-st which the wall 24 is to fit snugly. The downwardly facingend surface 56 of the wall 50 corresponds in. shape to the undersurfaceof the rim 26 of the lid, and the outer surface 57 of the the Wall 50and of the female punch corresponds in shape to the inner surface of theouter wall 27 of the lid. Spaced back from its lower end the punch 40has an upwardly facing annular peripheral ledge surface 58.

Around the punch 40 and spaced therefrom is a first cylindrical grippingring 60. The gripping ring 60 is an integral part of and protrudesdownwardly from a die member 61 which is held between the punch body 41and die block 38 by the studs 42, and the gripping ring 60 is thereforefixed in position relatively to the female punch. The gripping ring 60has a downwardly facing end surface 62 in a horizontal plane to whichthe end surface 56 of the punch extends. As will be explained, the outeredge 63 of the surface 62 acts as a foil severing edge. Above the edge63 the gripping ring has an inward bevelled jog 64.

Around the female punch 40 and within the gripping ring 60 is a firstcylindrical pressure ring 70 slidable longitudinally of the punch. Thepressure ring 70 is urged downwardly in the direction of the end of thepunch 40 by springs and plungers, a typical spring 71 and plunger 72being illustrated. The plunger 72 is sildable vertically in acylindrical passage 73 through the die member 61 and rests at its lowerend on the pressure ring 70. At its upper end the plunger has a head 74that travels in a cylindrical pasage 75 through the die block 38. Theupper end of the passage 75 is closed by a plug 76 fixed to the dieblock 38, the plug having a vent 77 from the passage 75 to atmosphere.The spring 71 is in compression between the plug 76 and head 74 andnormally, as shown in FIG. 3, the pressure ring is held in the positionwhere a downwardly facing ledge surface 78 of the ring abuts against theledge surface 58 of the female punch, the ledge surface 58 constitutinga stop which limits downward movement of the first pressure ringrelatively to the punch. It will been seen from FIG. 3 that with thepressure ring 70 in its lowermost position relatively to the punch 40,the downwardly facing end surface 79 of the ring is stepped back(upwardly) from the end surface 56 of the punch end wall 50 and from theend surface 62 of the first gripping ring 60.

The lower end of the pressure ring 70 is shown greatly enlarged in FIG.7, from which it will be seen that the ring 70 fits very closely aroundthe female punch 40, the clearance between the inner surface 80 of thering '70 and the outer surface 57 of the punch 40 being less than thethickness of the foil 32. The lower end surface 79 of the ring 70 isplane and horizontal, but in this surface is provided a downwardlyfacing smooth annular recess 81 around the female punch. As seen in FIG.7, the recess 81 is semi-circular in cross-section and with the surface80 it defines an annular knife edge 82 adjacent the outer surface 57 ofthe female punch.

Referring again to FIG. 3, the upper die assembly 36 includes a stripperplate 90 around the first gripping ring 60. The stripper plate 90 isnormally suspended from the die block 38 by plungers, one of which isillustrated at 91. The plunger 91 is fixed to the stripper plate,through a cylindrical passage 92 in the die block, and has a head 93that travels in a larger cylindrical die block passage 94 coaxial withthe passage 92. The stripper plate is pressed downwardly by springs, oneof which is shown at 95. The spring 95 is in compression between thestripper plate 90 and die block 38, and the plunger head 93 normallyrests against the step 96 in the die block between the passages 92 and94. In this position the plane lower surface 97 of the stripper plate islower than the end surface of the first gripping ring.

Let us now consider the lower die assembly 37. This assembly has astationary bed consisting of two blocks 100 and 101 resting on and fixedto a third block 102. The bed has a stepped cylindrical opening 103through the block 100 and coaxial with the female punch 40, with thefirst gripping ring 60 and with the first pressure ring 70 of the upperdie assembly. Around the upper circular edge 104 of the opening 103 thebed has a plane upper surface 105 on which the sheet of metal foil 32lies between the die assemblies. The sheet 32 must be sufficiently largeto cover the opening 103. The block 101 is secured at the bottom of theopening 103 with its upper surface 106 well below the level of the foilreceiving surface 105.

Located in and coaxial with the opening 103 is a male forming punch 110having a head 111 and integral stem 117. The head 111 has an upwardlyfacing surface 112 complementary to the surface 45, 52 of the femalepunch 40, having recesses 112a corresponding to the ridges 53 forforming the lid pattern 22. A conical pin 113 pointing upwardly from thecenter of the surface 112 is adapted to register with the opening 54 inthe female punch. The head 111 has an outwardly facing surface 114complementary to the surface 55 of the female punch but six foilthicknesses smaller in diameter, for a reason which will be explained.Below the surface 114 the head has a peripheral flange 115 whichprovides a downwardly facing ledge surface 115a and an upwardly facingledge surface 115b opposite the surface 56 of the female punch.

The stem 117 of the male punch is slidable vertically in a cylindricalpassage 116 through the bed block 101, and the stem has at its lower enda collar 117a travelling in aligned cylindrical passages 118, of greaterdiameter than the passage 116, in the blocks 101 and 102. In itsvertical sliding the male punch 110 is guided not only by its stem 117but also by a vertical cylindrical pin 119 screwed or pressed into theunderside of the head 111 and guided by the cylindrical wall of avertical passage 120 through the bed block 101. The pin 119 prevents thepunch 110 from rotating on a vertical axis, and thus ensures that therecesses 112a register with the ridges 53 on the knockout, the latterbeing prevented from rotating by a similar vertical pin (not shown)fixed to the knockout and extending upwardly into a passage (not shown)through the body 41 of the female punch.

The male punch 110 is urged upwardly by springs and plungers acting onthe underside of the head 111, one such spring 122 and plunger 123 beingillustrated. The plunger 123 is slidable vertically in a cylindricalpassage 124 through the bed block 101 and has at its lower end a head125 that travels in a cylindrical passage 126 through the bed block 102.The lower end of the passage 126 is closed by a plug 127 fixed to thebed block 102, the plug having a vent 128 from the passage 126 toatmosphere. The spring 122 is in compression between the plug 127 andplunger head 125, and normally holds the male punch 110 in its uppermostposition where, as shown in FIG. 3, the collar 117a abuts against thestep 129 between the passages 116 and 118, the upper surface 112 of themale punch being, at this uppermost position, lower than the foilreceiving surface 105 of the bed.

Within the bed opening 103 and around the male punch 110 but spacedtherefrom is a second cylindrical gripping ring 130 having a planehorizontal upper end surface 131 directly below and of the same innerdiameter as the end surface 62 of the first gripping ring 60. The secondgripping ring is urged upwardly by cylindrical plungers, one of which isshown at 132, in turn urged upwardly by a platform 133 and a spring 134.The upper end of the plunger 132 engages the underside of the ring 130,and the plunger extends vertically downwardly through a cylindricalpassage 135 through the bottom bed block 102. The lower end of theplunger 132 rests on the horizontal platform 133 which is slidablevertical on a rod 136 screwed at 136a into the underside of the bedblock 102. A boss 137 on the platform around the rod 136 helps to guidethe platform on the rod. The platform 1.33 is urged upwardly by thespring 134 which is in compression between the underside of the platformand a footing (not shown).

The second gripping ring 131) has on its inner surface an upwardlyfacing annular ledge surface or rest 138, and on this rest a secondpressure ring 140 is normally supported by a downwardly facing annularledge surface or stop 141 on the outer surface of the ring 140. On itsinner surface 142 the ring 140 has an upwardly facing ledge surface orstop 143 which, in the normal position shown in FIG. 3, engages thedownwardly facing ledge surface 115a of the male punch 110. Thus thelimit of upward movement of the rings 130 and 146, under the upwardurging of the spring 134, is determined by the uppermost position fo thesurface 115a of the male punch, as well as by the engagement of the boss137 with the underside of the bed block 192. In the uppermost positionof the ring 130 its end surface 131 is coplanar with the upper surface105 of the bed and is thus higher than the male punch.

The upper end of the second pressure ring 140 is best shown in FIG. 7.The upwardly facing end surface 144 of the second pressure ring isdirectly below the downwardly facing end surface 79 of the firstpressure ring 76, and the pressure rings have the same outside diameter.A short distance inwardly from its outer edge the surface 144 is steppeddownwardly, as at 144a, by an amount slightly exceeding three times thethickness of the foil 32, for a reason which will be explained when theoperation of the die is discussed. When the second pressure ring is inits uppermost position (FIG. 3), the highest part of the surface 144 (atthe outer edge) is coplanar with the surfaces 131 and 105. As shown inFIG. 7, the surface 144 has at its inner edge an annular ledge which isof ogee shape in cross-section, the ogee shape being concave at its top1441) adjacent the first pressure ring, and smoothly convex at thebottom 1440 adjacent the female punch 40 where it merges with the innersurface 142 of the second pressure ring.

The operation of the die will now be described in detail. The upper dieassembly 36 moves downwardly'from the position shown in FIG. 3, and asit does so the lower surface 97 of the stripper plate 90 comes intocontact with the foil sheet 32 lying on the bed surface 105. The spring95 compresses and under its force the stripper plate holds the foilsheet against the bed. As the upper die assembly moves furtherdownwardly, the smooth end surfaces 62 and 131 of the gripping rings 60and 130 cooperate, under the force of the spring 134, to grip betweenthem, as a fiat circular blank, that portion of the foil sheet that isbounded by the upper edge 104 of the opening 103. The descending ring 60cooperates at its outer edge 63 with the edge 104 to sever the flatcircular blank from the sheet 32. The second gripping ring 130 is forcedby the descending ring 60 to retract downwardly against the force of thespring 134, and the second pressure ring 140, which merely restsgravitationally on the rest 138, moves downwardly with the ring 130.Since the end surface 62 of the ring 60 is coplanar with the downwardlyfacing end surface 56 of the female punch 40, the surface 56 contactsthe upper surface of the foil simultaneously with the surface 62. As theupper die assembly descends, the flat foil blank, gripped between therings 60 and 130, comes into contact with the upper surface 112 of themale punch 11%. The spring 122 which urges the male punch upwardly isstiff and has sulficient force to sustain the male punch in itsuppermost position until the upper die assembly reaches the position ofFIG. 4. Thus, although the gripping ring 130 and the pressure ring 140slide downwardly in the opening 103, the male punch is sustained toprotrude beyond the end surfaces 131 and 144 of these retracting rings,and the male punch presses the foil blank into the recess 51 of thefemale punch and against the surfaces 45, 52, 55 and 56, as shown inFIG. 4. The conical pin 113 pierces the foil and protrudes into theopening 54, pushing some of the foil upwardly into the opening 54 andforming the opening 23 and baffle 23a in the foil. The large spring 134is relatively weak, and during the dishing of the central portion 34 ofthe foil blank into the recess 51 the spring causes the gripping rings60 and 130 to exert sufficiently light force on the peripheral portion33 to permit the latter to slip from between the plane end surfaces 62and 131 of the gripping rings and wrinkle generally radially, as alreadydescribed, without tearing. The coplanar surfaces 56 and 62 ensure thatthe peripheral portion slips straight out from between the surfaces 62and 131 in a direction normal to the vertical axis of the die.

At the position of FIG. 4 the peripheral portion 33 of the blank hascompletely slipped out of the grip of the gripping rings, but the blankis now firmly held between the male and female punches which tend topress flat the Wrinkles in what will be the wall 24 and rim 26 of thefinished lid. It has been stated that the surface 114 of the male punchhas a diameter six foil thicknesses smaller than the surface 55 of thefemale punch. Thus, as indicated in FIG. 7, there is a clearance ofthree foil thicknesses between the surfaces 55 and 114 when the punchesare in full engagement, this clearance providing room for the wrinkles30 and permitting the punches to cooperate fully in forming the pattern22 in the bottom of the lid.

In the downward movement to the position of FIG. 4 the upper surface 144of the second pressure ring 140 has not protruded above the plane endsurface 131 of the second gripping ring 130, the ring 140 havingdescended with the rest 138. Thus the ring 140 does not interfere withthe slipping of the peripheral portion of the blank from between thegripping rings. However, with the blank now free of the gripping rings,and the central portion of the blank pressed fully into the recess 51 ofthe female punch, the downward descent of the ring 140 is stopped by theupper surface 106 of the bed block 101. Continued downward movement ofthe upper die assembly to its bottom position, shown in FIG. 5, furtherretracts the gripping ring downwardly against the force of the spring134, and the female punch 40 forces the male punch 110 to retractdownwardly against the force of the spring 122. Thus the pressure ringpresses the wrinkled peripheral portion of the foil blank upwardlyagainst the outer surface 57 of the female punch.

The inner surface 142 of the ring 140 is complementary to and slidableover the outer surface 57 of the female punch. As indicated by FIG. 7,the clearance between the surfaces 57 and 142 slightly exceeds threetimes the thickness of the foil 32. Thus, although wrinkles 30 may causeparts of the peripheral portion 33 of the blank to be three times foilthickness, these wrinkles do not cause seizure and tearing of theperipheral portion between the relatively moving surfaces 57 and 142. Aspreviously mentioned, the end surface 144 is also stepped downwardly, asat 144a, by an amount slightly exceeding three times foil thickness.This is done to prevent pinching of the wrinkled peripheral portionbetween the pressure rings 70 and 140, for as the upper die assemblymoves downwardly from the position of FIG. 4 to its bottom position,FIG. 5, the non-retracting ring 140, resting against the stop 106,engages the end surface 79 of the ring 70 before the peripheral portionhas been completely moved from between the rings '76 and 140. However asseen in FIG. 7, engagement of the rings '70 and 140 can only take placenear the outer edges of the end surfaces 79 and 144, and after suchengagement but prior to the arrival of the upper die assembly at theposition of FIG. the part of the wrinkled peripheral portion 33 not yetpressed against the outer wall 57 of the descending female punch extendsinto the clearance between the ends of the rings 70 and 140. By way ofexample, for a foil thickness of 0.0018 inch, a clearance of 0.0060 inchis satisfactory between the surfaces 79 and 144a and between thesurfaces 57 and 142.

The engagement of the rings 70 and 140 forces the ring 70 to remainstationary as the upper die assembly finishes its movement downwardly tothe position of FIG. 5; the ring 70 thus retracts relatively to thefemale punch 40 against the force of the Spring 71, which compresses. Inthe position of FIG. 5 the ring 70, held upwardly relatively to thepunches, has its knife edge 82 positioned higher than the edge of thefoil. As seen in FIG. 7, the recess 81 defines with the ogee shapedsurfaces 144b and 1440 a cavity 150 of substantially the shape desiredfor the bead 28, the cavity being open towards the outer surface 57 ofthe female punch below the knife edge 82.

The bottom postion of FIG. 5 having been reached, the upper die assemblynow begins to move upwardly. On the upward or return movement of theupper die assembly, from the position of FIG. 5 to that of FIGS. 6 and7, the spring 71 is able to expand from its compressed condition and itholds the ring 70 in engagement with the ring 140 and the ring 140against the stop 106. However the spring 122 moves the male punch 110upwardly with the female punch 40, and thus the edge of the foil isforced against the knife edge 82 which turns the foil into the cavity150. By the time the position of FIGS. 6 and 7 has been reached, thepunches, gripping the foil, have moved sufiiciently far upwardlyrelatively to the pressure rings 70 and 140 that the edge of the foilhas been forced to curl outwardly and then inwardly through 360 degrees,and the bead 28 is thus formed, completing the lid.

The spring 134 moves the gripping ring 130 upwardly, following thegripping ring 60, and at the position of FIG. 6 the rest 138 is broughtinto engagement with the ledge surface 141 of the pressure ring 140. Atthe same time the ledge surface 58 of the female punch engages thesurface 78 of the pressure ring '70, and consequently the rings andpunches all rise until they are restored to their normal positions ofFIG. 3. The bevelled jog 64 (on the ring 60) and the stripper plate 90ensure that the rising ring 60 does not foul the sheet 32. The pressurering 140 during the last part of its upward travel presses the completedlid by its head off the male punch 110, and the lid is freed from thefemale punch by a downward tap on the plunger 46 of the knockout 43. Thelid may then be blown from between the die assemblies by a blast of air.The foil sheet 32 is shifted on the bed to bring another portion overthe opening 103, and the operation of the die is repeated.

It will be understood that the form of the invention herewith shown anddescribed is a preferred example and various modifications can becarried out without departing from the spirit of the invention or thescope of the appended claims.

What I claim as my invention is:

1. A die for making a lid from a blank of metal foil, comprising a firstdie assembly and a second die assembly normally spaced from the first,the die assemblies having a forward and return movement, the first dieassembly including a female forming punch having a peripheral end walldefining a recess at the face of the punch, the wall having an innersurface, an end surface and an outer surface, and a first pressure ringaround and slidable relative to the female punch along the outer surfaceof the female punch, the second die assembly including a male formingpunch cooperable with the female punch on forward movement of the dieassem blies to press the central portion of the blank into the recessthus pulling the peripheral portion of the blank inwardly, and a secondpressure ring around the male punch, the pressure rings havingengageable end surfaces, the second pressure ring being slidablerelatively to the female punch along the outer surface of the femalepunch in a direction away from the end surface of the peripheral wall topress the peripheral portion of the blank against said outer surfacewhile the male punch holds the central portion in the recess of thefemale punch, means positioning the second pressure ring on forwardmovement of the die assemblies to achieve sliding of the second pressurering relative to the female punch along the outer surface of the femalepunch, in said direction, only after the central portion of the blankhas been pressed fully into the recess of the female punch, the firstpressure ring having a foil catching edge adjacent said outer surfacefor curling the edge of the blank outwardly from said outer surface,said foil catching edge when the end surfaces of the pressure rings areengaged defining with the second pressure ring a foil curling cavity forforming an outwardly cured stiffening head on the peripheral portion ofthe blank while the male punch holds the central portion in the recess,and means positioning the pressure rings to achieve sliding thereofrelative to the female punch along the outer surface of the female punchin a direction opposite to said direction to catch and curl the edge ofthe blank after the pressing of the peripheral portion of the blankagainst said outer surface.

2. A die as claimed in claim 1, including means for limiting movement ofthe first pressure ring along the female punch towards said end surfaceof said wall whereby the first pressure ring is always stepped backrelative to said end surface, and means outside the pressure rings forgripping the peripheral portion of the blank in a slip grip under whichthe peripheral portion is pulled inwardly and wrinkles generallyradially without tearing as the central portion of the blank is pressedinto the recess.

3. A die as claimed in claim 2, wherein first spring means urge the malepunch towards the female punch, and after the central portion of theblank has been pressed into the recess of the female punch the latter oncontiued forward movement of the die assemblies retracts the male punchagainst the force of the first spring means, the positioning means forthe second pressure ring preventing retraction of the second pressurering with the male punch whereby the second pressure ring press% theperipheral portion of the blank against the outer surface of the femalepunch.

4. A die as claimed in claim 3, wherein the positioning means for thepressure rings include second spring means urging the first pressurering towards the second pressure ring, the second pressure ring whenprevented from retracting on forward movement of the die assembliesbeing stationary forcing the first pressure ring to retract against thesecond spring means, and the second spring means on initial returnmovement of the die assemblies holding the first pressure ring instationary engagement with the second pressure ring while the firstspring means move the male punch from retracted position thus forcingthe edge of the blank against the foil catching edge and into the foilcurling cavity.

5. A die for making a lid from a blank of metal foil, comprising a firstdie assembly and a second die assembly normally spaced from the first,the die assemblies having a forward and return movement, the first dieassembly including a female forming punch having a peripheral end walldefining a recess at the face of the punch, the wall having an innersurface, an end surface and an outer surface, and a first pressure ringaround and slidable relative to the female punch along the outer surfaceof the female punch, the second die assembly including a male formingpunch cooperable with the female punch on forward movement of the dieassemblies to press the central portion of the blank into the recessthus pulling the peripheral portion of the blank inwardly, and a secondpressure ring around the male punch, the pressure rings havingengageable end surfaces, the second pressure ring being slidablerelative to the female punch along the outer surface of the female punchin a direction away from the end surface of the peripheral wall to pressthe peripheral portion of the blank against said outer'surface while themale punch holds the central portion in the recess of the female punch,means positioning the second pressure ring on forward movement of thedie assemblies to achieve sliding of the second pressure ring relativeto the female punch along the outer surface of the female punch, in saiddirection, only after the central portion of the blank has been pressedfully into the recess of the female punch, the first pressure ringhaving a foil catching edge adjacent said outer surface for curling theedge of the blank outwardly from said outer surface, said foil catchingedge when the end surfaces of the pressure rings are engaged definingwith the second pressure ring a foil curling cavity for forming anoutwardly curled stiffening beadon the peripheral portion of the blankwhile the male punch holds the central portion in the recess, and meanspositioning the pressure rings to achieve sliding thereof relative tothe female punch along the outer surface of the female punch in adirection opposite to said direction to catch and curl the edge of theblank after the pressing of the peripheral portion of the blank againstsaid outer surface, the first die assembly including a first grippingring around the first pressure ring and the second die assemblyincluding a second gripping ring around the second pressure ring, thegripping rings having end surfaces cooperable on forward movement of thedie assemblies to grip the peripheral portion of the foil blank in aslip grip under which the peripheral portion is pulled inwardly withouttearing, the positioning means positioning the pressure rings, duringthe aforesaid gripping and pressing of the blank into the recess of thefemale punch, with the second pressure ring not protruding beyond theend surface of the second gripping ring and the first pressure ring notprotruding beyond the end surface of the first gripping ring, the firstgripping ring being fixed relative to the female punch, and spring meansurging the second gripping ring towards the first gripping ring, thesecond gripping ring being slidable longitudinally of the secondpressure ring, the spring means having sufliciently light force topermit the peripheral portion of the blank to slip from between the endsurfaces of the gripping rings when the central portion is being pressedinto the recess of the female punch.

6. A die as claimed in claim 5, wherein the spring means normallyposition the second gripping ring with its end surface protruding beyondthe male punch.

7. A die as claimed in claim 6, wherein the end surface of the firstgripping ring is coplanar with the end surface of the end wall of thefemale punch.

8. A die as claimed in claim 7, wherein, as the central portion of theblank is pressed into the recess of the female punch, the first grippingring retracts the second gripping ring against the force of the springmeans whereby the male punch protrudes beyond the end surface of theretracting second gripping ring.

9. A die for making a lid from a blank of metal foil, comprising a firstdie assembly and a second die assembly normally spaced from the first,the die assemblies having a forward and return movement, the first dieassembly including a female forming punch having a peripheral end walldefining a recess at the face of the punch, the wall having an innersurface, an end surface and an outer surface, and a first pressure ringaround and slidable relative to the female punch along the outer surfaceof the female punch, the second die assembly including a male formingpunch cooperable with the female punch on forward movement of the dieassemblies to press the central portion of the blank into the recessthus pulling the peripheral portion of the blank inwardly, and a secondpressure ring around the male punch, the pressure rings havingengageable end surfaces, the second pressure ring being slidablerelative to the female punch along the outer surface of the female punchin a direction away from the end surface of the peripheral wall to pressthe peripheral portion of the blank against said outer surface while themale punch holds the central portion in the recess of the female punch,means positioning the second pressure ring on forward movement of thedie assemblies to achieve sliding of the second pressure ring relativeto the female punch along the outer surface of the female punch, in saiddirection, only after the central portion of the blank has been pressedfully into the recess of the female punch, the first pressure ringhaving a foil catching edge adjacent said outer surface for curling theedge of the blank outwardly from said outer surface, said foil catchingedge when the end surfaces of the pressure rings are engaged definingwith the second pressure ring a foil curling cavity for forming anoutwardly curled stiffening head on the peripheral portion of the blankwhile the male punch holds the central portion in the recess, and meanspositioning the pressure rings to achieve sliding thereof relative tothe female punch along the outer surface of the female punch in adirection opposite to said direction to catch and curl the edge of theblank atfer the pressing of the peripheral portion of the blank againstsaid outer surface, the second pressure ring having, for defining thefoil curling cavity, a smooth annular recess which surrounds the femalepunch when the end surfaces of the pressure rings are engaged, saidrecess being defined by a surface of the second pressure ring that isogee shaped in cross-section, the ogee shaped surface being smoothlyconvex adjacent the female punch and concave adjacent the first pressurering when the end surfaces of the pressure rings are engaged.

10. A die as claimed in claim 9, wherein the foil catching edge is aknife edge defined by a smooth annular recess around the female punch inthe first pressure ring, the latter recess cooperatnig with the recessin the second pressure ring to define the foil curling cavity.

11. A die as claimed in claim 10, wherein the foil catching edge of thefirst pressure ring is closer than the thickness of the foil to theouter surface of the female punch.

12. A die as claimed in claim 11, wherein the second pressure ring isslidable relatively to the female punch over the outer surface of thefemale punch with a clearance slightly exceeding three times thethickness of the foil to accommodate wrinkles in the foil.

13. A die as claimed in claim 12, wherein the pressure rings engage eachother near the outer edges of their end surfaces and have between theirend surfaces, inwardly of where they engage, a clearance slightlyexceeding three times the thickness of the foil so as not to pinchwrinkles in the peripheral portion of the blank as it is pressed againstthe outer surface of the female punch.

14. A die for making a lid from a blank of metal foil, comprising afirst die assembly and a second die assembly normally spaced from thefirst, the die assemblies having a forward and return movement, thefirst die assembly including a female forming punch having a peripheralend wall defining a recess at the face of the punch, the wall having aninner surface, an end surface and an outer surface, and a first pressurering around and slidable relative to the female punch along the outersurface of the female punch, the second die assembly including a maleforming punch cooperable with the female punch on forward movement ofthe die assemblies to press the central portion of the blank into therecess thus pulling the peripheral portion of the blank inwardly, and asecond pressure ring around the male punch, the pressure rings havingengageable end surfaces, the second pressure ring being slidablerelative to the female punch along the outer surface of the female punchin a direction away from the end surface of the peripheral wall to pressthe peripheral portion of the blank against said outer surface While themale punch holds the central portion in the recess of the female punch,means positioning the seocnd pressure ring on forward movement of thedie assemblies to achieve sliding of the second pressure ring relativeto the female punch along the outer surface of the female punch, in saiddirection, only after the central portion of the blank has been pressedfully into the recess of the female punch, the first pressure ringhaving a foil catching edge adjacent said outer surface for curling theedge of the blank outwardly from said outer surface, said foil catchingedge when the end surfaces of the pressure rings are engaged definingwith the second pressure ring a foil curling cavity for forming anoutwardly curled stiffening bead on the peripheral portion of the blankwhile the male punch holds the central portion in the recess, and meanspositioning the pressure rings to achieve sliding thereof relative tothe female punch along the outer surface of the female punch in adirection opposite to said direction to catch and curl the edge of theblank after the pressing of the peripheral portion of the blank againstsaid outer surface, the first die assembly including a first grippingring around the first pressure ring and the second die assem blyincluding a second gripping ring around the second pressure ring, thegripping rings having end surfaces cooperable on forward movement of thedie assemblies to grip the peripheral portion of the foil blank in aslip grip under which the peripheral portion is pulled inwardly withouttearing, the positioning means for the second pressure ring comprisingan upwardly facing rest on the second gripping ring, said restsupporting the second pressure ring, during the aforesaid gripping andpressing of the blank into the recess of the female punch, with thesecond pressure ring not protruding beyond the end surface of the secondgripping ring.

References Cited in the file of this patent UNITED STATES PATENTS1,884,708 Jeneson Oct. 25, 1932 2,899,922 Wheeler Aug. 18, 19592,968,270 McChesney Jan. 17, 1961

1. A DIE FOR MAKING A LID FROM A BLANK OF METAL FOIL, COMPRISING A FIRSTDIE ASSEMBLY AND A SECOND DIE ASSEMBLY NORMALLY SPACED FROM THE FIRST,THE DIE ASSEMBLIES HAVING A FORWARD AND RETURN MOVEMENT, THE FIRST DIEASSEMBLY INCLUDING A FEMALE FORMING PUNCH HAVING A PERIPHERAL END WALLDEFINING A RECESS AT THE FACE OF THE PUNCH, THE WALL HAVING AN INNERSURFACE, AN END SURFACE AND AN OUTER SURFACE, AND A FIRST PRESSURE RINGAROUND AND SLIDABLE RELATIVE TO THE FEMALE PUNCH ALONG THE OUTER SURFACEOF THE FEMALE PUNCH, THE SECOND DIE ASSEMBLY INCLUDING A MALE FORMINGPUNCH COOPERABLE WITH THE FEMALE PUNCH ON FORWARD MOVEMENT OF THE DIEASSEMBLIES TO PRESS THE CENTRAL PORTION OF THE BLANK INTO THE RECESSTHUS PULLING THE PERIPHERAL PORTION OF THE BLANK INWARDLY, AND A SECONDPRESSURE RING AROUND THE MALE PUNCH, THE PRESSURE RINGS HAVINGENGAGEABLE END SURFACES, THE SECOND PRESSURE RING BEING SLIDABLERELATIVELY TO THE FEMALE PUNCH ALONG THE OUTER SURFACE OF THE FEMALEPUNCH IN A DIRECTION AWAY FROM THE END SURFACE OF THE PERIPHERAL WALL TOPRESS THE PERIPHERAL PORTION OF THE BLANK AGAINST SAID OUTER SURFACEWHILE THE MALE PUNCH HOLDS THE CENTRAL PORTION IN THE RECESS OF THEFEMALE PUNCH, MEANS POSITIONING THE SECOND PRESSURE RING ON FORWARDMOVEMENT OF THE DIE ASSEMBLIES TO ACHIEVE SLIDING OF THE SECOND PRESSURERING RELATIVE TO THE FEMALE PUNCH ALONG THE OUTER SURFACE OF THE FEMALEPUNCH, IN SAID DIRECTION, ONLY AFTER THE CENTRAL PORTION OF THE BLANKHAS BEEN PRESSED FULLY INTO THE RECESS OF THE FEMALE PUNCH, THE FIRSTPRESSURE RING HAVING A FOIL CATCHING EDGE ADJACENT SAID OUTER SURFACEFOR CURLING THE EDGE OF THE BLANK OUTWARDLY FROM SAID OUTER SURFACE,SAID FOIL CATCHING EDGE WHEN THE END SURFACES OF THE PRESSURE RINGS AREENGAGED DEFINING WITH THE SECOND PRESSURE RING A FOIL CURLING CAVITY FORFORMING AN OUTWARDLY CURED STIFFENING BEAD ON THE PERIPHERAL PORTION OFTHE BLANK WHILE THE MALE PUNCH HOLDS THE CENTRAL PORTION IN THE RECESS,AND MEANS POSITIONING THE PRESSURE RINGS TO ACHIEVE SLIDING THEREOFRELATIVE TO THE FEMALE PUNCH ALONG THE OUTER SURFACE OF THE FEMALE PUNCHIN A DIRECTION OPPOSITE TO SAID DIRECTION TO CATCH AND CURL THE EDGE OFTHE BLANK AFTER THE PRESSING OF THE PERIPHERAL PORTION OF THE BLANKAGAINST SAID OUTER SURFACE.